This invention relates to a pipe connector and more particularly to a connector device for joining adjacent sections of tubular piling assemblies without requiring rotation therebetween.
In the production of oil and gas from offshore wells, it is often necessary to locate the drilling and production platforms of wharfs at an offshore site. These platforms are anchored to the sea floor by tubular piles. The length of each of the piles may exceed a thousand feet. The handling of such large tubular piles is facilitated by building up the piles from 100-150 foot sections joined together in an end-to-end manner utilizing pile connectors to interconnect two adjacent sections.
Several types of pile connector have previously been utilized including interrupted screw thread connectors, snap-type locking ring connectors, and engagable dog-type connector. Each type of prior pile connector has one or more undesirable inherent characteristics or limitations.
In the interrupted screw thread type connector, the foremost shortcoming is that adjacent pipe sections must be relatively rotated to establish a connection therebetween and such rotation requires application of a large amount of torque. Necessarily, large equipment must be utilized to accomplish this rotation which is an inconvenience in an offshore environment. Additionally, the screw thread connector is expensive to manufacture, requires excessive care and handling to prevent damaging the threads, and requires precise alignment during connection.
The prior snap-type locking ring connectors have experienced failures because improper loading of the locking ring results in a high stress concentration in the machined receptacle which receives the locking ring. The locking ring also has a tendency to move to an unlocked position as a result of the vibrations encountered as the pile sections are driven into the sea floor.
The dog-type connectors which have previously been available utilize radially engagable dogs to secure one section of piling to the next section. In these prior dog-type connectors the connection is preloaded to secure the piling sections together. However, the vibrations which develop during offshore driving of piles may cause the connector to vibrate loose thereby relieving its preload. Thus, vibration can cause the radially moveable threaded screws, which are used in these connectors, to seize and gall thereby preventing the screws from being rotated after the driving operation. Also, the dogs tend to become brittle and are subject to bending or breaking because of small imperfections machined in the connectors used with the dogs. Further, because such dogs must be moved in a radial direction to disengage one section of the piling from another, an excessive amount of space must be provided for them in the connectors.
In a pile driving connector, it is desirable to attain fast, easy connector make up without requiring the application of torque i.e., without relative rotation of the piling sections. It is also desirable that the connector maintain preloading, i.e., the continuous urging together of the abutting ends of adjacent tubular pile sections should be insured. Moreover, the connector should be mechanically uncomplicated, economical to manufacture, and capable of withstanding bending, axial tension, and axial compressive stresses experienced during driving.
Accordingly, it is an object of the present invention to provide an improved pile driving connector which achieves fast, easy make up without the need for relative rotation between the pile sections.
Another object of the invention is to provide a snap-type pile driving connector that maintains preload between abutting pipe ends.
A further object of the invention is to provide a nonrotating pile driving connector having rigid structural integrity for withstanding bending, axial tension, and axial compressive stresses during driving.
A still further object of the invention is to provide a pile driving connector which is economical to manufacture and efficient in use.